New in Symfony 4.3: Deprecated the Role and SwitchUserRole classes

A long-standing goal of Symfony is to simplify certain parts of the security
system. In Symfony 3.3 we deprecated the RoleInterface and in Symfony 4.1 we
deprecated the AdvancedUserInterface. In Symfony 4.3 we've deprecated the
Role and SwitchUserRole classes.

In practice there are few real benefits of using objects instead of strings to
represent roles. Eventually it only led to overhead because you had to call
Role::getRole() to get the actual string representing the role.

If your app uses the full-stack Symfony framework, you probably don't need to
change anything because you are already defining roles with raw strings. If you
use the standalone Security component, you need to refactor any code dealing
with Role classes (or define your own Role class to keep using classes).

If you are impersonating users in your app, you need to refactor any code
that uses SwitchUserRole to use instead the new SwitchUserToken: